The papers in Organometallics, 10,1421-1431,1991; Inorg. Chem., 34, 4092-4105,1995; J. Organomet. Chem., 527(1-2), 263-276,1997; and 10 Inorg. Chem., 35(6), 1518-28,1996, report the reaction of bis (iminophosphoranyl) methane (BIPM) which are typically aryl substituted on the phosphorus atom and the nitrogen with Group 8, 9 or 10 metal halides (chlorides) further comprising at two weakly coordinating ligands (L) such as nitrites or cyclooctadiene, afforded several products depending on the reaction time, type of ligand or nature of the metal. The product could be a N--C chelating type product or a N--N chelating product (similar to those of the present invention). ##STR1##
The products contain alkyl bridges between the phosphinimine groups and the references do not disclose the pyridyl bridged compounds of the present invention. Further, none of the references teach or suggest the use of such compounds for the polymerization of alpha olefins.
U.S. Pat. No. 5,557,023 issued September, 1996 teaches the use of some phosphinimines complexes to oligomerize alpha olefins. However, the complexes disclosed are not bisphosphinimine complexes. Rather, the complexes are of the structure indicated below. ##STR2## wherein R, Q, etc. are as defined in the patent. The structures disclosed in the patent are not the bisphosphinimines of the present invention. While the reference does teach oligomerization, it does not suggest polymerization.
WO 98/30609 patent application published Jul. 16, 1998 assigned to E. l. du Pont de Nemours teaches the use of various complexes of nickel to polymerize alpha olefins. The most structurally similar complex in the disclosure is compound XXXXI at the middle of page 9 and the associated description of the various substituents. However, the compound does not contain a pyridyl bridge. Rather, the nickel atom completes the cyclic structure in the middle of the compound. The reference does not contemplate or disclose compounds of the present invention which have a pyridyl bridge between the bisphosphinimine functionality. The reference fails to disclose the subject matter of the present invention.
There are a number of patents and papers by Brookhart and/or Gibson disclosing the use of Group 8, 9 or 10 metals to polymerize olefins. However, such papers did not teach the copolymerizations (e.g. WO 98/27124). The present invention provides olefin copolymerization using an iron based catalyst.